Due to a "sorting error" my S2 package arrived a week late. Better late than never, right? Here is the first test print in fine detail plastic. I'm almost done with the handrail designs. The chassis, on the other hand, needs a lot more work. I might get rid of the Shorty's circuit board completely from this design to make assembly a lot easier.
doesn't it seem that the model prints seem to be getting worst! in Smooth fine Detailed plastic. Your models is outstanding but I have notice some poor printing at shapeways lately. I have sent several back because of this some are even hard to scrap off the surface! going to take a lot of cleaning. I guess the brass one will be much better. Great work! They also take more time now to get things!
Yep, a brass print should be much better in surface quality. On the other hand, I am excited about the new Accura Xtreme plastic that just became available. It's supposed to be very smooth and very sturdy. I have a test print on the way so we will see.
I finally finished designing the handrails. There will be two types of pilots on each fret. There is the regular one with a foot platform and an alternate with a "closed" pilot(no platform). Also, separate grab irons will be included. The shell will have holes for the grab irons. This will make it easier to put stripe decals across the front of the long hood and the rear cab. It will be about a month before the first samples arrive. The frame is coming along, too. It will have a "rack" that holds a circuit board for lights or a DCC board or none at all. There is also a clamp that holds the resistor in place like on the SW1500.
Just an suggestion... If you have the detail parts etched in stainless steel they are stronger and less sensitive for bending while handling the finished locomotive. /Frank Verstuurd vanaf mijn ANE-LX1 met Tapatalk
And the side louvers might be better as etched part, too. Nevertheless I’m very exited by this new addition to Z, great job as always
This project is still moving forward. I've been experimenting with other materials for 3D printing because I am trying to find better alternatives to brass printing. With brass prints, you generally get a good surface quality compared to plastic prints. Today, Shapeways announced a new smooth finish to one of their plastic materials. I have ordered an S2 shell in this new plastic to see if it can replace brass as main material for the shell. If it works out, the price of the shell will be 30% cheaper with a smoother surface to boot.
I'm curious how much the brass shell contributes to the weight and therefore electrical pickup and traction of these small engines. When normal Z scale diesels are $160, I don't really mind paying for the brass parts if they significantly improve performance.
If a plastic shell becomes viable, I would adjust the frame to be heavier to compensate. However... (Incoming long winded over explanation!) Adding more weight usually doesn't help because the design of the shorty is working against the modeler in several ways. The shorty's powered truck is not designed to pitch and roll like an AZL truck found on a GP38 or any six axle loco. It only rotates on one axis. This prevents all the wheels from touching on uneven tracks or turnouts. Combine this with traction tires and the electrical pickup of the powered truck is usually around 25 to 50% at best. Nearly all the electrical pickup comes from the other truck because it has more freedom of movement. Some SW1200 modelers have soldered wires to dummy truck. I bet they noticed a significant improvement in electrical pickup. I personally like to add the springs to the dummy truck to vastly improve connection to the circuit board. I use the springs that come with MTL body mount couplers. The ones in the capsule, not the coupler springs. I place them over the two copper poles of the dummy truck so they always press against the circuit board. The engine will go days without ever stalling or needing any help. Even on dirty uneven track it keeps going.
Finally some progress! The etched metal handrail parts arrived. They need revisions but version 2 should be the final one. The shell will have two versions. One with grab irons "molded in" and one with pilot holes (seen below) to mount the grab irons to the body. After a couple failed experiments designing the chassis, I'm close to finishing this one. I have decided to go with a split frame much like a traditional model locomotive. There will be two brass halves of the frame and a plastic insert between. The brass, while not the best conductor, seems to provide plenty of electricity to the motor. That means no pesky shorty circuit board will be needed for this frame. The best part is that various circuit boards and DCC decoders will slip right in with no soldering. You can wire the motor to the frame for analog or connect to the decoder if going digital. The frame is not pictured below because I want to show the final version. It should be delivered in a week or so.
My idea for a three part chassis didn't work out. I tried a plastic frame sandwiched between two metal shells that would hold the motor and trucks in place. The problem is the parts would never line up and the motor just ended up grinding the gears. I had to revert back to a single part brass chassis. There are still a few more bug to fix where the shell meets the chassis but I'm nearly finished.
So, what do you guys do to remove the build step lines off a brass RP model? Do you sandblast them or hand sand them?
Hi Robert, I did sand the shell a little by hand using small grade sand paper. But shapeways brass is printed in wax and lost wax casted in brass. At least my sw1200 shell came out acceptable, needed just a little touch up. /Frank Verstuurd vanaf mijn ANE-LX1 met Tapatalk
All Shapeways brass prints are put into a tumbler. Even if you didn't order the polished finish it still gets time in the tumbler. More often than not, I don't have to do any sanding at all. If it does I use diamond files.
